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regionbase [2014/09/16 14:26] (current)
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 +===== The <regionBase> Element =====
 +==== Definition and Usage ====
 +
 +The [[regionbase|<regionBase>]] element groups a set of [[region|<region>]] elements, each
 +of which may contain another set of nested [[region|<region>]] elements, and so
 +on, recursively.
 +
 +Each [[regionbase|<regionBase>]] element is associated with a class of devices where
 +presentation will take place.  To identify the association, the
 +[[regionbase|<regionBase>]] element defines the //device// attribute.  When the
 +attribute is not specified, the presentation takes place in the same device
 +that runs the NCL player.
 +
 +There are two different types of device classes: active and passive.  In an
 +active class, a device is able to run some media players for [[media|<media>]]
 +element presentations.  In a passive class, a device is not required to run
 +media players, only to exhibit a bit map or a sequence of audio samples
 +received from another device.
 +
 +The "deviceClass" property of a [[media|<media>]] element is initialized with the
 +//device// value, if the [[media|<media>]] element indirectly refers to a
 +[[region|<region>]] element inside a [[regionbase|<regionBase>]], by using a
 +[[descriptor|<descriptor>]] element.
 +
 +The chosen class also defines the global environment variables (properties
 +of the settings object ---[[media|<media>]] element of
 +"application/x-ncl-settings" type): "system.screenSize(i)",
 +"system.screenGraphicSize(i)", and "system.audioType(i)".
 +
 +The "systemScreen(1)" and "systemAudio(1)" are reserved to passive classes,
 +and "systemScreen(2)" and "systemAudio(2)" are reserved to active classes.
 +
 +The [[regionbase|<regionBase>]] element that defines a passive class may also have a
 +region attribute.  This attribute is used to identify a [[region|<region>]]
 +element in another [[regionbase|<regionBase>]] associated with the parent device that
 +creates the bit map sent to the passive class; in the specified region the
 +bit map must also be exhibited.  The "system.parentDeviceRegion(i)" property
 +of the settings object ([[media|<media>]] element of "application/x-ncl-settings"
 +type) is initialized with the //region// attribute value.
 +
 +==== Syntax ====
 +^ Element ^ Attributes ^ Content ^ Parent ^
 +| [[regionbase|<regionBase>]] | //id//, //device//, //region// | ([[importbase|<importBase>]] <nowiki>|</nowiki> [[region|<region>]])+ | [[head|<head>]] |
 +==== Attributes ====
 +
 +^ Name ^ Value ^ Description ^
 +| //id// | It may receive any string value that begins with a letter or an underscore and that only contains letters, digits, <".">, and <"_">. | The //id// attribute uniquely identifies the element within a document. |
 +| //device// | "systemScreen(i)" or "systemAudio(i)".  Where the attribute is not specified, the presentation shall take place in the same device class that runs the NCL player. | The //device// attribute identifies the class of devices where presentation will take place. |
 +| //region// | IDREF. | The //region// attribute identify a [[region|<region>]] element in another [[regionbase|<regionBase>]] associated with the parent device that creates the bit map sent to the passive class; in the specified region the bitmap must also be exhibited. |
 +
 +
 +
  
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